Exaxtly, wait for days, months, years…depending on what it is, you can get deals.
Or the other odd ball, I was trying to buy an out of print railroad book about ten years ago. Commonly going for over $150…eventually after watching this go on for well over a month, then one week day, during an off hour I got a copy of the same book for about $60. Then a week later, they were all high again.
The secret to eBay is when two or more people want something, it does not work with just one.
And sometimes it is silly, for example, a little while ago a battery Rigi set, used, taterd box, missing stuff, went for over $360, while one of the good 120V powered dealer ones went for $120?!?!?!?!?!?